Isochromosome 6p and deletion of 6q characterize two related cytogenetic clones in a patient with immunoblastic lymphoma.

In a case of immunoblastic lymphoma we observed the presence of either a deletion of the long arm of chromosome 6 or of an isochromosome, i(6p), which occurred alternatively in metaphase cells. This suggests a selective pressure for loss of heterozygosity of genes located on 6q and is in accordance with the hypothesis that one or more tumor suppressor genes might be located on the long arm chromosome 6.